Electric heater.



K. SGHLUTER.

ELECTRIC HEATER.

APPLICATION FILED MAY 20, 19 08.

Patented July 6, 1909.

"UN TED STATES PATENT OFFICE.

KARL SCHLIITER, OF KIEL-GAARDEN, GERMANY, ASSIGNOR TO FRIED. KRUPP AKTIEN- GESELLSCHAFT GERMANIAWERFT, OF KIEL-GAARDEN, GERMANY.

ELECTRIC HEATER.

No. 927,173. Specification of Letters Patent. I Patented July 6, 1909.

Application filed May 20, 1908. Serial No. 433,921

To all whom it may concern: I I

Be it known. that I, KARL SOHLI'JTER, a

subject of the Emperor of Germany, and a resident of Kiel-Gaarden, in the Empire of vGermany, have invented certain new and useful Improvements in Electric Heaters, of which the following is a specification.

The subject of the present invention is an electric heater, having its resistance members constructed-0f nickel tubes. Heaters with such resistance members possess especial efficiency because the material of the resistance possesses a high electrical temperature coefficient, a high specific resistance, and a high heat radiating coefficient, and,-because the form in which it is ossible' to embody the metal, in producing t e resistance, causes the surrounding air to contact with the greatest possible superficial area, thereby preventin over heatin of the resistance.

One em odiment oft e invention is shown by way of exam le in the accompanying drawings, in which Figure 1 shows the heater in longitudinal section, and Fig.2 shows the heater in crosssection.

In a housing A, a coin aratively large number of thin walled nickel tubes B are mounted through insulation in transverse sheet metal walls C, so as to constitute a condenser type of structure. In the walls G and between the tubes B are provided a large number of bores c. The nickel tubes B, through the medium of suitably disposed sheet metal strips D, are interposed in series in an uninterrupted conductor for electrical current. The ends of this conductor terminate in two binding posts E mounted through insulation'u on the housing A. In the end walls of the ousing A are located an air intake F and an air outlet G. The former stands in communication with theatmosphere, while the latter leads to the place of use of the warmed air, as for example, the combustion chamber of an internal combus.

tion engine.

If the bindin posts are suitably connected to a source 0 electricity, electric current flows through the circuit provided by the walls 0 which communicates with the space surrounding the group of tubes, and would become highly heated in conse uence of the great contact surface provided y the resistances B.

Experiments have shown that a heater constructed in the described manner will stand acurrent of thirty amperes per square millimeter of conductor section and at the same time, is selfrotect'ed against overheating, by the higii coeflicient of the nickel. The heater is also shown by experiments to withstand temperature fluctuations of 900 degrees centigrade electrical temperature.

and over with swift air currents, without danger of fracturing the nickel tubes. J

Furthermore, since nickel tubes are only slightly oxidized at very high temperatures, the heater Having t us described the invention, what possesses a great lasting quality. I

is claimed and desired to be secured by Letters- Patent is In an electric heater, the comblnatlon with a housing open at the top and provided in one end-wall with an air-intake and in the otlier end-wall with an airoutlet; of a topplate adapted to close said housing; tubular resistance members of nickel open at both ends and suspended from said top-plate with the open ends of said tubes adjacent to the intake and outlet respectively; means for nsulating said tubes each from each and from said top-plate and connections whereby said tubes are joined separately in series.

The foregoing specification signed at Kiel, Germany, this'5th day of May, 1908.

KARL SOI-ILUTER.

In presence of- BRUNO BEHsE,

GEORG RIEBEs. 

